From DE 101 20 063 A1, a method is known for producing metallic profile components for motor vehicles, wherein a starting material provided in the form of a strip is fed to a roll-forming unit and is shaped into a rolled profile. Prior to or subsequent to passing through a roll-forming unit, the starting material or the rolled profile is inductively heated to a temperature required for hardening and then quenched by a cooling unit and hardened. The rolled profile is fed via a downstream calibration unit to a cutting unit which cuts the rolled profile into separate profile components.
A method for producing a metallic shaped component in which a semi-finished product of an unhardened hot-formable steel sheet is shaped into a component blank by means of a cold-forming method is known from DE 102 54 695 B3. At its edges, the blank is then trimmed to an edge contour corresponding to the component to be produced. Finally, the trimmed component blank is heated and press hardened in a hot-forming tool. Already after hot forming, the component has the desired edge contour, so that a final trimming of the edge of the component can be dispensed with.
From DE 100 33 493 C2, an apparatus for the heat treatment of impact beams for automobiles is known, which comprises a step feeder for guiding a plurality of impact beams thereon and orderly and continuously feeding the impact beams in a predetermined direction, and a conveying unit and a guide unit, both being orderly positioned behind the step feeder, wherein a heat-treating unit is provided, which is used for heating the impact beams using an annular induction coil while guiding the impact beams from the rotating and moving unit to a center of said induction coil so as to allow the impact beams to pass through the center of the induction coil.
From DE 197 43 802 C2, a process for the manufacture of a metallic shaped component is known, wherein the component is formed from a steel with a specified steel alloy and partial areas of the plate are heated to a temperature between 600° C. and 900° C. in a period of less than 30 seconds, and the plate partially thermally treated thereby is shaped in a pressing tool to form the shaped component, and the shaped component is then heat-treated in the pressing tool. Components with bottoms of different hardnesses are to be produced in this way.
A component produced according to the so-called tailored blank process, which has an area formed with a higher strength than an adjacent area, is known from JP 2002020854 A.
A partial heat-treatment for components and a device therefor is known from JP 2005330504 A.
A single-part metal sheet semi-finished product produced by shaping, which has defined zones of different strength, and a method for its production are known from DE 10 2004 046 119 A1. In order to achieve the desired strengths in the defined zones, the defined zones are subjected to heating with subsequent rapid cooling. In order to achieve this high temperature gradient, it is provided that a forming tool is used, and in particular, a cooled roller of a rolling tool.
From U.S. Pat. No. 4,482,793, an apparatus for inductively heating a plurality of identical elongated workpieces is known.
From the published research project P584/July 2005 by the Forschungsvereinigung Stahlanwendung e.V., it is known to incorporate rectangular reinforcing members in the form of elongated columns (FIG. 35) into an open hollow profile with a quadrangular or square cross section.
Moreover, it is known to reinforce beams by applying rectangular reinforcing member (FIG. 36).
Moreover, it is known from the research project P584 by the Forschungsvereinigung Stahlanwendung, page 74, in analogy to the patent specification DE 197 43 802 C2, to harden an elongated hollow profile in certain areas.
Also from the published research project P584 by the Forschungsvereinigung Stahlanwendung, July 2005, page 76, it is known to form an open profile with different wall thicknesses along its length, wherein these different wall thicknesses were achieved by rolling the raw material in a manner flexible with regard to thickness, with transitional areas being formed in this case between thicker and thinner areas (FIG. 38).
In another embodiment according to the state of the art, so-called tailored blanks, in which thickness varies over the cross section because different steel thicknesses or steel grades are laser-welded transversely relative to the profile's longitudinal direction, are being used for forming the hollow profiles (FIGS. 39, 40).
Moreover, it is known (FIGS. 41, 42) to insert inserts inside in areas in which a profile is to be reinforced, and to optionally fasten them in order to reinforce the material in this area.
Furthermore, it is also known (FIGS. 43, 44) to provide inserts on the outside on a corresponding profile, in reversal of the above-mentioned embodiment.
In its various embodiments, the aforementioned prior art has specific drawbacks.
The production of so-called tailored blanks, that is, in particular laser-welded plates, with different material thicknesses or different material grades is disadvantageous in that on the one hand, the welding seam may introduce an undefined area of hardness, and on the other hand, that there are often sudden transitions between the individual areas. In addition, such sheets are rather expensive because they require a complex production process. Moreover, such parts must be handled precisely so that the welding seam is always placed exactly at the correct position during and after roll-profiling.
In the case of profiles that have been thickened by means of inserts on the inside or the outside in areas of higher load, it is also disadvantageous that such a configuration is complex and leads to different response behaviors during a subsequent rolling process. If such a doubling process is carried out after rolling, this is at least rather complex. Moreover, there is once again the drawback that there are rather sudden property transitions.
This also concerns profiles that have been hardened or heat-treated in partial areas along their length.
It is a drawback in the case of flexibly rolled tube profiles that process control is more complex than in the case of tube profiles of the same thickness, because the position of the transitional areas and the thick and thin areas must be axially precisely defined, so that no spatial or local displacements and thus different response behaviors under strain occur over the entire production process.
When column-shaped or rectangular elements are inserted in hollow profiles, it is disadvantageous that this is extraordinarily complex and expensive, and that it again results in rather sudden transitions in the response behavior.
Moreover, thickened portions in the material and internal attachments increase the weight of the components, which runs contrary to the general principles, in particular in the case of vehicle construction, of building lighter.
The aforementioned sudden transitions in the response behavior in bending tests are disadvantageous because sharp buckling with an abrupt failure often occurs in the case of a crash. Such a failure behavior, which is undesirable, is shown in FIG. 45.
It is an object of the invention to provide a method for producing hardened profiles and in particular of hardened roll formed open profiles which permits providing, in a cost-effective, quick and reliable manner, roll-formed and light profiles with different areas of hardness in which the transitional areas are obtained in a smooth and effective manner.
It is another object to provide a device for carrying out this method which has a simple structure, permits a high throughput and allows a high flexibility with regard to different profile shapes.